Volkswagen on Tuesday informed workers at its lone U.S. plant in Chattanooga, Tenn., that it is appealing a decision to allow the United Auto Workers union to seek collective bargaining rights for a small group of skilled workers.

The regional director of the National Labor Relations Board last month rejected Volkswagen’s arguments that only the entire 1,400-member hourly workforce at the plant should be allowed to vote on union representation, and not just the “micro unit” of 165 skilled-trades workers.

The company said in a notice to plant workers that the challenge won’t halt the two-day union vote by the smaller group of employees scheduled to begin Thursday.

“The decision to appeal is based on Volkswagen Chattanooga’s consistent position that the Chattanooga workforce is one integrated team and our One Team concept is a critical component of our success,” Volkswagen said in the announcement.

The UAW has criticized Volkswagen for hiring a law firm that touts its expertise in “strategies for lawful union avoidance,” and charges that the aggressive stance against the union is at odds with the German automaker’s stated mission of co-determination between workers and management.

“We’re disappointed that Volkswagen continues to argue against employees’ rights that clearly are protected under federal law,” Gary Casteel, the UAW’s secretary-treasurer, said in a statement. “We’re calling on Volkswagen to drop this appeal and instead refocus on the core values that made it a successful brand, including environmental sustainability and employee representation.”

Volkswagen has questioned the timing of the UAW’s latest push, given the company's struggles to cope with its diesel emissions cheating scandal.

The UAW retorts that the Chattanooga plant is alone among Volkswagen’s plants around the world without formal labor representation. “That needs to change if the plant is going to play a meaningful role in Volkswagen’s comeback story,” Casteel said.